Hapalopilus nidulans (also known as Hapalopilus rutilans) is a species of polypore fungus in the family Polyporaceae. Officially described in 1821, it was transferred to its current genus Hapalopilus six decades later. It is commonly known as the tender nesting polypore, purple dye polypore, or the cinnamon bracket. This widely distributed species is found on five continents. It grows on the fallen or standing dead wood of deciduous trees, in which it fruits singly, in groups, fused, or in overlapping clusters. Fruit bodies are in the form of kidney-shaped to semicircular, cinnamon-orange-brown brackets. The underside of the fruit body features a yellowish to brownish pore surface with tiny angular pores, from which spores are released.